> I think that the major indicator here, as to the strength of the imperfect, may
> be found in the similar construction in verses 23 & 24. The imperfect finite verbs
> are both in tandem with aorist participles: EPIQEIS + EPHRWTA . . . ANABLEYAS +
> ELEGEN. The imperfects are indicating action which takes place concurrently with
> that of the participles. Thus, we might render these lines as "while he laid hands
> upon him, he was asking him 'Do you see anything?' Looking up, he was saying 'Not
> very well . . . .' So, he touched his eyes again . . ."

In other words, the
> imperfects are providing a continuously-moving dialogue against which the action of
> the participles take place.

[Moon]
This statement seems to imply that Jesus's speaking
was already in progress when Jesus laid his hand upon the man.
It is true of
"When she entered the room, he was reading the book".

But in our cases, the events described by the participles ( EPIQEIS,
ANABLEYAS) take place before the event described by the main
verbs in imperfect, according to our world knowledge.
So, Daniel's explanation does not seem to reveal what is
going on in these verses.

Except for clauses that describe timeless truths, every clause should
have the reference time (RT) relative which the situation of the
clause is described. The RT of the participial clause ANABLEYAS is
the time point after Jesus asked the question. Relative to this
time point, the aorist participial clause introduces the situation
where the blind man looks up. The RT of the clause ELEGEN is
determined relative to this situation; The RT of the main clause
may refer to the beginning, the middle, or the end of this situation,
because the aorist participle clause describes a situation as a whole
If the participle were imperfect, the RT of the main clause would
refer to the middle of the situation of the participle.

In the current example, the RT of ELEGEN refer to the time
point at the end of the looking up. The speaking of the blind
man is described in imperfect relative to this RT, because
the author wants to describe it vividly, as in slow motion in
a movie. The situation described in marked tense, e.g. imperfect,
receives emphasis. So, the observation that the imperfect
main clause describes the situation concurrent with the situation
described by the aorist participle does seem to hold only
in some cases, depending on the world knowledge and the
discourse context.